package com.bw.entity;

public class ClassA {


    private ClassB classB;

    public void setClassB(ClassB classB) {
        this.classB = classB;
    }

    public void m1(){
        if (classB == null){
            System.out.println("classB 这个属性注入失败");
        }else {
            System.out.println("classB 这个属性注入成功");
        }
    }
}
